well i just got around to trying the headphone amp. it is pretty good(used hd800,k702). however i feel first and foremost it is a dac. headphone amps over $500 seem like they are mostly going to be better. over a grand and a lot better. benchmarks hpa-2 is better as well. a lot of people do not like that though. overall i think they could sell this box for $1,500 and get away with it fine.
I see what you mean by it being mainly a DAC, but I can't help but remember how good the headphone output was out of the Teac UD-H01 with the T1's, that's why I wonder if UD-501 is even better. Is there anything wrong with the headphone out? Like, its the any noise, hissing at higher volumes, distortion, channel imbalance, lack of bass or extension, or does it in general sound like a good, lets say mid-fi amp for 300,400 dollars? Does it get loud enough with the HD800? Any reference headphone amp you can compare the output to more specifically?
Sorry for asking so much, but currently for me it's a choice between getting the UD-501 to power the T1's, and then later I get a new separate amp. I dont expect the UD-501 to be the end game headphone amp, I just expect it to be good enough to not ruin the sound of the T1's and not compromise the sound of the DAC section of the UD-501 too much.